Shell as used herein shall mean all pressure holding parts of the vessel in contact with the service fluid, including heads, nozzles, manholes and manhole covers.

这里的壁板指与系统介质接触的所有压力部件，包括封头、设备口、人孔及人孔盖板。

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The leakage event of a non-asbestos gasket was taken place at the manhole flanged joint of a boiler after more than one-year service.

一台废热锅炉人孔用非石棉纤维橡胶垫片服役一年多后发生泄漏。

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